Draw polygon with holes

[crocpulsar]

Hello,

I need to draw polygon with holes, the holes are also polygons, how do to build a graphics item like this in qt4?
I am thinking to construct it with QPainterPath, but I am not sure how to do it.

Any ideas?

[janus]

Hi,

not sure if this is the best solution, but I am doing something like this:

QPainterPath path;
QPolygonF p;
//add outer points
path.addPolygon(p);
QPainterPath inner;
//add inner points
inner.addPolygon(p);
path = path.subtracted(inner);

QPainterPath path;
QPolygonF p;
//add outer points
path.addPolygon(p);
QPainterPath inner;
//add inner points
inner.addPolygon(p);
path = path.subtracted(inner);

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[vratojr]

Hi, It seemed to me that this version is faster:

QPainterPath path;
QRegion clip(path);
 
QPainterPath sub;
clip-=QRegion(sub);
 
paint.setClipRegion(clip);
 
paint.fillPath(path,brush);

QPainterPath path;
QRegion clip(path);

QPainterPath sub;
clip-=QRegion(sub);
					
paint.setClipRegion(clip);

paint.fillPath(path,brush);

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[crocpulsar]

Thanks for these suggestions.
I will try them tomorrow and get back to here. I am just too drunk now.
Need to get some sleep

[crocpulsar]

Hi,
I think I will use the first method right now. If I need to write a customized graphics item, the second one may be a good choice.

BTW: is there any particular reason that the second method is faster than first one?

Thanks for help!